Environmental factors that affect the concentration of P and N in faecal samples collected for the determination of nutritional status

Abstract

Faecal samples have been proven to be valuable in determining the nutritional status of wild herbivores. It is often, however, difficult and impractical to collect dung as it is dropped. In this study, the effect of various environmental factors that may influence P and N concentrations in faeces were investigated. Factors examined were rain, age of samples, presence of dung beetles, method of storage, length of storage, the effect of fungal growth (mould) on poorly dried samples, and drying period of samples. Results indicate that samples should only be collected from fresh dung pads that are still wet and which show no signs of dung beetle activity. Collecting of samples shortly after a rain storm should be avoided. Samples can be air-dried in a ventilated room or oven-dried at 60 @C without any effect on the nutrient concentrations, but care must be taken to avoid fungal growth during the drying period. Dried samples can be stored in paper bags for up to 1 year before analysis. The individual variation in P concentration is larger in browsers than in grazers and more samples should thus be collected from browsers to be representative of the herd when samples are pooled. During the period of this study, no difference between males and females was found and samples representing the herd can therefore be collected randomly. Faeces from juvenile impala are only representative of the herd once they have been weaned.